Firing mechanism for firearms



Sept. 17, 1963 G. WILHELM 3,103,753

FIRING MECHANISM FOR FIREARMS Filed Dac. 22. 1960 2 Sheets-Sheet 1 IN VENTOR G/IAY W/U/A-Z/V Jazz/162W &

A ATTORNEYS.

Sept. 17, 1963 G. WILHELM 3.1 3.7

FIRING MECHANISM FOR FIREARMS Filed Dec. 22. 1960 2 Sheets-Sheet 2 IN VENTOR G/I/W W/Lf/L'LM fdtzrmzfidzztwz A ATTORNEXF.

United States Patent 7 Claims. (CI. 42-69) This invention relates to a firing mechanism for firearms and more specifically to a firing mechanism for firearms in which the cartridge is fired by the axial movement of a striker member.

Safety, of course, is of the utmost importance in a firearm. Every effort of the manufacturer of the firearm is bent toward making each gun as safe as possible. However, difierent guns will have varying degrees of safety as the uses to which each gun is to be put will have a bearing on the matter and will almost always, to some degree, affect the extent to which the objective may be achieved in that particular firearm.

An important aspect of the safety problem is to so construct each firearm that the chances of its accidental discharge will be minimized. Thus, one objective, which is constantly present in the manufiacture of each firearm, is the provision of a firing mechanism for that firearm which will not (tall off, that is, accidentally discharge when the gun is dropped or otherwise mishandled during normal usage.

The safest firing mechanism with respect to fall off is one in which all of the components of the mechanism are balanced. A component is balanced when its center of gravity coincides with its pivot point so thattwhenever the gun is jarred there are no inertia forces on the component tending to pivot the component about its pivot point. This is understood in the art but practical. con siderations in the design of a gun make it difii cult to achieve a completely balanced firing mechanism. Limitations imposed by other aspects of the guns design frequently will not permit the components of the firing mechanism to be balanced.

To some extent the unbalance of the firing mechanism can be compensated for by providing the gun with a heavy trigger pull. Trigger pull is the force required to move the trigger to its firing position. With a heavier trigger pull stronger springs may be employed to maintain the engagement of the components of the firing mechanism.

Accordingly, a greater jarring force will be required to cause the gun to fall off. However, the heavier trigger pull will not completely compensate for the unbalance of the firing mechanism and the gun will still be apt to fall off if jarred.

Furthermore, a heavy trigger pull is often very undesirable because it tends to reduce the accuracy with which the weapon can be fired. With a light trigger pull the person firing the gun is less apt to waiver in his aim as the effort and time required to pull the trigger are reduced. Increasing the trigger pull, therefore, may be an unacceptable solution to the problem of fall off and even in those instances where it is acceptable only amounts to a partial solution achieved at the expense of accuracy.

'In general, there are two principal types of firing mechanisms for firearms. One type employs a spring loaded pivoted hammer member which, upon release, swings to strike the cartridge in the chamber of the gun. In the other principal type, a striker member is provided that is spring loaded so as to be constantly urged in an axial direction. Upon release, the striker member either strikes the cartridge directly or strikes a firing pin which, in turn, fires the cartridge.

Each type of mechanism has advantages. One important advantage of the striker type of firing mechanism on the trigger and the firing of the cartridge. However,

a disadvantage of the striker type of firing mechanism has been that it has heretofore required a relatively high trigger pull.

The present invention has for its general object the provision of a firing mechanism for those firearms in which an axially movable striker member is employed that will increase the safety of the firearm with respect to accidental discharge and yet, one which will permit a lighter trigger pull than heretofore possible with the same degree of safety. More specifically, the invention has for its object the provision of a firing mechanism incorporating a sea-r and a connector for the sear in which the force required to disengage the scar and sear connector is minimized without increasing the tendency of these parts to disengage should the firearm be accidentally dropped or otherwise mishandled.

Briefly, and in general, the invention comprises a firing mechanism utilizing an axially movable striker member for firing the cartridge. The firing mechanism incorporates a rotatable sear that is normally disposed in the path of the striker member in order to engage the striker member and prevent axial movement thereof. Engagement of the striker member with the sear tends to rotate the sear out of the path of the striker member but the engagement is maintained by a sear connector which engages the sear and prevents it from so rotating. The scar connector is pivotally mounted and is actuated to a searreleasing position by a trigger. Although the sear and striker member engage each other with considerable force, applicants sear construction is such that the amount of torce required to disengage the sear connector from the sear is very much less.

is accomplished by directing theforce vector of the sears engagement with the striker member closely adjacent the center of rotation of the sear. At the same time the force vector of the engagement between the sear and the sear connector is directed substantially tangent to the periphery of the sear at a point that is spaced a substantially greater distance from the center of rotation than is the force vector of the engagement of the striker member on the sear.

Another important aspect of the invention is that the sear mechanism is compact so that it is capable of use in 'various types of firearms, including hand gone In preferred form, the shape of the sear roughly approaches the circular in that most of the peripheral portions of the sear are approximately equidistant from the center of the sear. The point about which the sear rotates is 'also located approximately at the center of the sear.

It is preferred that the center of rotation coincide as nearly as possible with the sears center of gravity. When this condition is achieved, the sear is balanced and the tendency of the sear to rotate when the gun is jarred is very much reduced.

While firing mechanisms embodying the present invention may advantageously be used in the usual mechanical type of trigger system in which a finger-actuated trigger lever is employed to disengage the sear connector from the sear, the invention may also be used to great advantage in firearms having electric trigger mechanisms. This type of trigger mechanism has recently been successfully employed in the type of firearm used in shooting matches where accuracy is of the utmost importance. Since an electromagnet is employed to disengage the sear connector trom the sear, the trigger pull can be made as light as desired.

For the purpose of illustrating the invention, two presently preferred embodiments of the invention are shown in the drawings and these embodiments will be described in detail hereinafter. However, it is to be understood that the following detailed description and the accompanying drawings are by way of example only and are not intended to define or restrict the scope of the invention, the claims appended hereto being relied upon for that purpose.

In the drawings,

FIG. 1 is a schematic view of a mechanical firing mechanism embodying the invention;

FIG. 2 is a similar view showing the firing mechanism of FIG. '1 in a firing condition;

FIG. 3 is a schematic view of an electrically actuated firing mechanism embodying the invention; and

FIG. 4 is a similar view showing the firing mechanism of FIG. 3 in a firing condition.

Referring first to FIGS. 1 and 2, there is shown schematically a firing mechanism composed entirely of mechanical elements. The firing mechanism is intended for use with a firearm employing an axially movable striker member. The striker member may either be of the type that strikes the cartridge directly or of the type that first strikes a firing pin which, in turn, strikes the cartridge.

The forward portion only of such a striker member is shown in the drawing. A striker spring "11 constantly urges the striker member 10 axially toward the left in the direction indicated by the arrow 12. However, axial movement of the striker member 10 in this leftwardly direction is normally arrested by a rotatable sear 14 and the lower forward end portion 16 of the striker member 10 is cut away at an angle to provide a face 16 that engages a corerspondingly angled face 20 on the sear 14. The angles of the faces 18, 20 with respect to the horizontal are not exactly the same but are slightly ditferent. As a result the engagement between the striker member 10' and the sear 14 is more nearly a point to point contact rather than a surface to surface contact. However, the difference in the angles is so slight as not to be apparent in the drawings.

The engagement of the striker member '10 with the sear 14 is such that the force of the spring on the striker member tends to rotate the sear in a clockwise direction as shown in the drawings. Rotation in this direction, however, is prevented by a sear connector 22 which engages the sear in a manner to be described hereinafter.

The sear v14 is mounted on a pin 24, preferably located at the sears center of gravity, and is shaped so as to be compact. As shown in the drawing and as is preferred, the shape of the sear 14 is roughly circular in that most of the peripheral portions of the sear are approximately equidistant from the center of the sear. Inasmuch as the sear 14 is made from a uniform material, such as hardened steel, the geometric center of the sear will also be the center ofv gravity of the sear. If the center of the pin 24 coincides with the center of gravity the sear 14 will be balanced and, as was stated above, this condition is preferred.

The sear 14 may be conveniently formed from a circular blank of metal that is machined to provide the desired configuration. The face 20 engaging the striker member 10 is provided at the upper right quadrant of the blank and the angle of the face 20 is selected so that the vector 26 of the force of engagement between the sear 14 and the striker member 10 will pass to the right of the center of pin 24 as shown in the drawings, that is, to that side of the pin 24 which will cause the sear to rotate clockwise out of engagement with the striker member 10. The value of the face angle is such that the force vector 26 will pass through or closely adjacent the pin 24.

The scar is also machined away in the upper left quadrant, to provide a surface 28 starting at or just above the highest point of the face 20. The surface 28 extends substantially across a major portion of the sear 14 and provides the necessary clearance between the sear 14 and the striker member 10 after the latter has been released from its cocked position. -In order to balance the sear, a similar amount of metal is machined away in the lower right quadrant to provide the surface 30. A notch 32 is provided at a point substantially opposite the face 20. One side of the notch 32 forms a shoulder 34 that engages one end 36 of the sear connector 22. Two substantially radial shoulders 38, 40 are also formed on the sear 14. One shoulder 38 serves as an abutment that engages a limiting pin 42 to limit the clockwise rotation of the sear. The other shoulder 40 engages the end of a leaf spring 44 which serves to urge the sear 14 in a counterclockwise direction. A second limiting pin 46 engages the surface 31} and limits the counterclockwise rotation of the sear.

The sear connector 22 comprises a lever that is pivotally mounted at its center on a pin 48. End 36 of the sear connector abuts against the shoulder 34 on the sear 14 and locks the sear against clockwise rotation under the urging of the striker member. The opposite end 50 of the sear connector 22 engages one arm 52 of a balanced trigger 54. A spring 56 positioned between the sear connector 22 and a stationary part of the frame 58 of the gun constantly urges the sear connector 22 toward engagement with the sear 14.. The spring 56 also urges the trigger 54 counterclockwise toward its normal nonfiring position, and therefore acts as a trigger spring.

In operation, the firing mechanism is actuated by a pull on the finger piece 6% of the trigger 54 in a right hand direction -(as seen in the drawing). This rotates the trigger 54 counterclockwise about the pin 62v against the force of the spring 56. The counterclockwise rotation of the trigger 54 pivots the sear connector 22 in a clockwise direction causing the end 36 to be withdrawn from the shoulder 34 on the sear 14. After the disengagement of the sear connector 22 from the sear 14 is complete, the sear is free to rotate in a clockwise direction under the urging of the striker member 10. As soon as the sear 14 has completely rotated out of the path of the striker member 10 that member moves axially to the left to discharge the cartridge in the chamber of the gun (not shown). In its travel the sear rotates through an angle of approximately 30.

Little force is required to actuate the firing mechanism because the force required to disengage the sear connector 22 from the sear 14 is very small, notwithstanding the fact that the force of engagement between the sear 14 and the strike member 10 is substantial. The difference in the two forces results from the fact that the vector 26 of the force of engagement between the scar and the striker member is directed so as to pass through or closely adjacent the pin 24. The force vector thus passes close to the sears center of rotation and has a small lever arm. The resultant turning moment on the sear is accordingly reduced.

At the same time the force of engagement between the sear 14 and sear connector 22 occurs at a peripheral point of the sear, hence, at a distance from the sears center of rotation that is considerably greater than that of the force vector 26. This results in a large lever arm for this engaging force and since the turning moment on the sear is not very great, the force at the point of engagement of the sear 14 and the sear connector 22 is not great. The force required to disengage the sear connector 22 from the sear 14 is equal to the force of engagement between the parts multiplied by the proper coefficient of friction. Since the coefiicient of friction for dry metal to metal contact varies from 0.15 to 0.20 it will be seen that the disengaging force will be quite small. Consequently, the trigger pull required to actuate the firing mechanism can be very light.

If all of the elements of the firing mechanism are balanced, as are the elements shown in FIG. 1, a very safe gun is produced. Notwithstanding the relatively light trigger pull of such a firing mechanism it will not easily fall 011. The location of the centers of gravity of the various parts approximately at their centers of rotation reduces the inertia forces that would otherwise tend to rotate the various parts should the gun be jarred or mishandled.

The compactness of the sear, which has the advantage of facilitating the assembly of the firing mechanism into a firearm, also has the advantage of permitting wider manufacturing tolerances than would otherwise be possible. It will be readily appreciated that the positioning of the face 20 with respect to the pin 24 is very important since the angle which the face 20* makes with respect to the pin 24 will determine the distance at which the force vector 26 will pass. The greater the distance between the face 20 and the pin 24 the more exacting must be the manufacturing tolerances in machining the face 20 since any error in the face angle will be multiplied by the dis tance to the pin. By providing a sear in which the peripheral portions are approximately equidistant from the pivot point, a construction is achieved which permits wide manufacturing tolerances since the face is thereby brought into fairly close proximity to the pin 24 and a small error in the angle of the face 2%) will not greatly increase the distance between the center of rotation and the point through which the force Vector 26 passes.

The invention may also be embodied in an electrically actuated firing mechanism and such an embodiment is shown in FIGS. 34. As before, the forward portion only of a striker member 110 is shown, the striker member 110 being constantly urged axially toward the left by a striker spring (not shown). Movement of the striker member 110 is prevented by a rotatable sear 112 which engages the lower forward end portion 114 of the striker member and both the sear 112 and the striker member 110 are, accordingly, provided with engaging face portions 118, 120 respectively. The angles of the engaging faces 118, 120 are again slightly different but the dilference is too slight to appear in the drawings.

The sear 112 is mounted for rotation on a pin 122 and is roughly circular in shape so as to be compact. Like the sear in the preceding embodiment of the invention described above, the sear 112 may be conveniently formed from a circular blank of suitable material machined to give the desired configuration. The upper left hand quadrant of the sear 1:12 is machined away as at 124 so as to provide access for the striker member 110 when that member moves forwardly in an axial direction. The engaging faces 118, 120 of the sear and striker member are such as to produce a turning moment that tends to rotate the sear 112 in a clockwise direction as shown. However, rotation of the sear 112 is normally prevented by a sear connector 126 which engages the sear 112; and holds it against such clockwise rotation. Accordingly, the sear is provided with a notch 128; one side of which forms a shoulder for engagement with the sear connector 126.

The scar 112 is also machined to form two radial shoulders 132, 134 that alternatively abut a limiting pin 135 to limit rotation of the sear 112 in both the clockwise and counterclockwise directions. In addition, the seat 112 is machined to form another shoulder 136 that engages the end of a leaf spring 138. The leaf spring 138 constantly urges the sear 112 in a counterclockwise direction and, thus, serves as a return spring for the sear.

In the particular embodiment of the invention shown in FIGS. 3 and 4, the sear connector 126 comprises an elongated lever arm pivotally mounted at one end 1411 on a pivot pin 142. Intermediate its ends the sear connector 126 is machined to form a shoulder 144 that engages the side 1311 of the notch 128 on the sear. A curved portion '146 lies just above the shoulder 144 to provide clearance for the adjacent portion of the sear 112. The sear connector 126 is also provided with a long straight face 148 extending from underneath its intermediate portion to its free end. The face 148 is disposed substantially parallel and closely adjacent to the active face 150 of an electromagnet 152. A spring 154 positioned between the sear connector 126 and the frame 156 of the gun constantly urges the sear connector 126 toward engagement with the sear 112.

The electromagnet 152 is electrically connected to a source of electricity which, in preferred form, comprises one or more batteries 157 suitably located within the gun and is also connected to an insulated contact 158. The contact 158' is positioned at the trigger guard 160 immediately behind the finger piece 162 of the trigger 164.

In operation, the firing mechanism is actuated by a pull on the finger piece 162' toward the right (as viewed in the drawing). This pivots the trigger 164 counterclockwise against the force of a spring 166 positioned between the frame 156 of the gun and the end of one leg 163 of the trigger 164. Since the batteries and the trigger are both grounded an electric circuit is completed when the finger piece 162 of the trigger touches the contact 158. Energization of the electromagnet 152 pulls the shoulder 144 on the sear connector 126 out of engagement with the shoulder 1 30 on the sear 112 thereby permitting the sear to rotate through approximately 20 in a clockwise direction. This releases the striker member and fires the gun.

The last described embodiment of the invention requires a very light pull on the trigger in order to fire the gun. This results from the fact that, as before, the angle of the face 118 on the sear 112 is such as to direct the vector 170 of the force of engagement between the striker and the sear through or closely adjacent the pin 122. For the reasons described in connection with the first embodiment, this results in a light engagement between the scar and the sear connector. This engagement is light enough to permit the employment of an electromagnet for withdrawing the sear connector from the sear. Since the trigger is, thereby, mechanically isolated from the sear connector, the pull on the trigger can be made as light as desired. The firing mechanism may, thus, be advantageously incorporated into firearms where accuracy is of the utmost importance.

At the same time the firing mechanism is a relatively safe one. The configuration of the sear 112 is such that, whilethe sear is not entirely balanced, it is approximately balanced. The trigger 164 itself is substantially balanced. The most unbalanced element in the firing mechanism is the sear connector 126. This is a result of the necessity of presenting a substantially parallel face 148 to the electromagnet 152 in order to obtain a more uniform attraction between the magnet and the sear connector. The pivot point 142 of the sear connector 126 is, for this reason, placed at a point some distance from the sear connectors center of gravity. Notwithstanding this unbalance, the firing mechanism is still many times safer than other firearms having a similarly light trigger pull. Since such weapons are used only by expert marksmen, the lowering of the guns resistance to fall ofif presents no great problems. Moreover, in firearms where space is available, the sear connector can be readily balanced by extending it on the opposite side of its pivot point 142.

The last described embodiment of the invention illustrates how other gun design factors may adversely affect the problem of achieving a gun that will not fall off. This embodiment of the invention was intended for use as a target pistol for international shooting competition. Accuracy was, accordingly, of the utmost importance and the gun has to be designed with an extremely light trigger pull.

One method of achieving an extremely light trigger pull is to employ an electric trigger. In a firing mechanism employing an electric trigger the trigger pull can be made as light as desired since the trigger is not required to actuate any other components of the firing mechanism but is used simply to close an electric circuit. The electromagnet actuated by the closing of the circuit supplies the force required to disengage the sear connector from the sear.

However, the small lightweight type of magnet which must be used does not have much pulling power. Tne force required to disengage the sear connector from the sear is therefore, necessarily small. In the customary type of firing mechanisms heretofore employed this disengaging force is seldom less than two pounds. Through the employment of the present invention this force is reduced to between two and four ounces. In the specific example shown in FIGS. 3-4 the face 118 on the sear 112 is disposed at an angle of 30 with respect to the direction of travel of the striker 118 and the force vector 170 is substantially tangent to the pin 122 as shown. The force of the striker spring on the striker 110 is 26 pounds, but may be as much as 35 pounds or more Without noticeably affecting the force required to pull off the sear connector. The principal radius of the sear 112 in this instance is .225 inch, and pivot pin 122 for the sear has a radius of .062 inch. The gap at the face of the magnet is desirably from .007 to .010 inch, and the electromagnet is designed to lift 14 ounces with a gap of .010 inch. An extremely fast lock time of from 1.6 to 1.9 milliseconds has been obtained with this gun, as compared to a lock time of 8 to 16 milliseconds in one of the most prominent free pistols used in international competition. The fastest lock time heretofore achieved in a commercially available firearm is from 5 to 6 milliseconds, this being accomplished in the so-called speed lock type of firing mechanism found in certain bolt-action target rifles. The present invention has therefore reduced the lock time of the gun to less than one-third the fastest time heretofore achieved. At the same time, it provides a light trigger pull combined with greater safety against accidental discharge of the gun.

What is claimed is:

1. A firing mechanism for firearms, said firing mechanism comprising a striker member spring loaded so as to be constantly urged in a firing direction; a pivot pin; a sear pivotable about the pivot pin, said sear having a first surface for engaging said striker member to prevent movement of said member in a firing direction, said surface being disposed so as to direct the vector of the force of the engagement of the striker member with the sear substantially toward the center of the pivot pin, said sear having a second surface; and a sear connector having a surface for engaging the second surface on the sear to prevent the sear from being pivoted by the striker member, said second surface being located at a distance from the center of the pivot pin substantially greater than the distance between the center of the pivot pin and the aforementioned vector of force, the vector of force, with respect to the pivot pin, being slightly off-center in a direction whereby force from the striker member will pivot the sear when the sear connector is disengaged from the second surface of the sear.

2. A firing mechanism as set forth in claim 1, wherein the rotatable sear is shaped so that its center of gravity and the center of the pivot point substantially coincide.

3. A firing mechanism as set forth in claim 1, wherein said first and second surfaces on the rotatable sear are substantially equidistant from the center of the pivot pin.

4-. A firing mechanism as set forth in claim 1, and trigger means mounted on a pivot pin for withdrawing the sear connector from engagement with said sear, said trigger means having a center 'of gravity substantially coinciding with the center of the pivot pin.

5. A firing mechanism for firearms, said firing mechanism comprising a striker member spring loaded so as to be constantly urged in a firing direction; a pivot pin; a sear pivotably mounted on the pivot pin, said sear having a first surface for engaging said striker member to prevent movement of said member in the firing direction, said surface being disposed so as to direct the vector of the force of the engagement of the striker member with the sear substantially toward the center of the pivot pin, said ear having a second surface; a scar connector having a surface for engaging the second surface on the sear to prevent the sear from being pivoted by the striker member, said second surface being located at a distance from the center of the pivot pin substantially greater than the distance between the center of the pivot pin and the aforementioned vector of force, the vector of force, with respect to the pivot pin, being slightly off-center in a direction whereby force from the striker member will pivot the sear when the sear connector is disengaged from the second surface of the sear; electromagnetic means for withdrawing the sear connector from engagement with said sear and a source of electric power and trigger means to supply power to said electromagnetic means upon actuation of said trigger.

6. A firing mechanism as set forth in claim 5 wherein said sear connector is provided with a face portion positioned closely adjacent said electromagnetic means and substantially parallel thereto.

7. A firing mechanism for firearms as set forth in claim 6 wherein said sear connector is pivotally mounted on a pivot pin at a point spaced at a relatively great dis tance from said electromagnetic means.

References Cited in the file of this patent UNITED STATES PATENTS 1,492,728 Hunt May 6, 1924 2,249,232 Smith July 15, 1941 2,274,195 Garrison Feb. 24, 1942 2,337,145 Albree Dec. 21, 1943 2,435,18 Reising Jan. 27, 1948 2,548,622 Sampson et al. Apr. 10, 195.1 2,564,960 Cubbage Aug. 21, 1951 2,856,717 Parke Oct. 21, 1958 

1. A FIRING MECHANISM FOR FIREARMS, SAID FIRING MECHANISM COMPRISING A STICKER MEMBER SPRING LOADED SO AS TO BE CONSTANTLY URGED IN A FIRING DIRECTION; A PIVOT PIN; A SEAR PIVOTABLE ABOUT THE PIVOT PIN, SAID SEAR HAVING A FIRST SURFACE FOR ENGAGING SAID STRIKER MEMBER TO PREVENT MOVEMENT OF SAID MEMBER IN A FIRING DIRECTION, SAID SURFACE BEING DISPOSED SO AS TO DIRECT THE VECTOR OF THE FORCE OF THE ENGAGEMENT OF THE STRIKER MEMBER WITH THE SEAR SUBSTANTIALLY TOWARD THE CENTER OF THE PIVOT PIN, SAID SEAR HAVING A SECOND SURFACE; AND A SEAR CONNECTOR HAVING A SURFACE FOR ENGAGING THE SECOND SURFACE ON THE SEAR TO PREVENT THE SEAR FROM BEING PIVOTED BY THE STRIKER MEMBER, SAID SECOND SURFACE BEING LOCATED AT A DISTANCE FROM THE CENTER OF THE PIVOT PIN SUBSTANTIALLY GREATER THAN THE DISTANCE BETWEEN THE CENTER OF THE PIVOT PIN AND THE AFOREMENTIONED VECTOR OF FORCE, THE VECTOR OF FORCE, WITH RESPECT TO THE PIVOT PIN, BEING SLIGHTLY OFF-CENTER IN A DIRECTION WHEREBY FORCE FROM THE STRIKER MEMBER WILL PIVOT THE SEAR WHEN THE SEAR CONNECTOR IS DISENGAGED FROM THE SECOND SURFACE OF THE SEAR. 